1. Field of the Invention
The present invention relates to a mobile communication terminal and corresponding method that processes input data based at least one or parameters corresponding to changeful radio channel states.
2. Background of the Invention
A mobile communication terminal allows people to wirelessly communicate with each other via a communication network including a MSC (Mobile Switching Center) and a plurality of BSs (Base Stations). Mobile terminals also provide the user with the ability to transmit data including symbols, numerals and characters as well as multimedia data.
In addition, mobile terminals use a variety of different communication techniques such as the Code Division Multiple Access (CDMA) technique, Time Division Multiple Access (TDMA) technique, Frequency Division Multiple Access (FDMA) technique, and Global System for Mobile Communications (GSM) technique. Further, the International Telecommunication Union (ITU) has selected the International Mobile Telecommunication 2000 (IMT-2000) system as the third generation (3G) mobile communication system to provide improved multimedia services.
In more detailed, the 3G system increases the mobile terminal's capabilities to include services such as a wireless LAN, digital multimedia broadcast, portable Internet, etc. These additional services use a High Speed Downlink Packet Access (HSDPA) method that is based on the asynchronous IMT-2000. The HSDPA method increases the downlink transmission speed and thus decreases the transmission delay.
Turning now to FIG. 1, which illustrates a related art transmitting mobile communication terminal. As shown, the terminal includes a Central Processing Unit (CPU) 100 for controlling various units of the terminal, and a Cyclic Redundancy Checksum (CRC) unit 200 for adding CRC bits to input data and for packeting the data, a channel coder 300 for performing a channel coding process for the packeted data. Also included is a Hybrid Automatic Repeat request (HARQ) transmission and reception processors 410 and 420 for processing the coded data based on a preset Forward Error Correction (FEC) coding rate, channel interleavers 500 and 510 for channel-interleaving the processed data, a modulator 600 for modulating the interleaved data, and an antenna 700 for transmitting the modulated data.
In more detail, FIG. 2 illustrates processes performed by the transmitting terminal shown in FIG. 1. As shown, the input data is packeted into a preset size (S210). That is, the mobile terminal receives data to be transmitted and adds CRC bits used for error detection to thereby enable the packeting of the data to have the preset size. Then, a channel coding process is performed on the packeted data (S220), and the channel-coded data is processed according to a preset FEC coding rate (S230). That is, when transmitting the packeted data, the mobile terminal uses a preset FEC coding rate to thereby improve an error correction function.
Next, the processed data is subject to a channel interleaving process (S240). The mobile terminal interleaves the processed data to reduce the probable loss of the data during the data transmission. The channel-interleaved data is then mapped to a physical channel (S250), and the mapped data is modulated and then transmitted (S260). Further, the mobile terminal modulates the mapped data using a preset method such as the BPSK, QPSK, 8PSK, 16QAM, 64QAM methods to thereby allow the transmission of the modulated data to a receiving side mobile terminal.
However, the related art mobile terminal transmits the data using a preset FEC coding rate, etc. regardless of a channel state, which disadvantageously affects a communication quality when the state of the channel changes.